Bone-in shoulder. I think it was $2/lb.
I take the shoulder out and cut it in half so I can fit each half in a 1 gallon ziplock. I cover in a dry rub and liquid smoke.
Here's my sous vide setup. I think my cooker only runs 700 watts, and pulses to maintain temp. I thought about putting it inside a cardboard box to help insulate, but I don't think I care that much.
Some people use an old cooler for their sous vide bath.
The neat thing about the cooler idea is you could take your meat with you and sous vide at your destination. I cooked the last pork shoulder at an Air BnB and it took up a lot of cooler space.